1. Field of the Invention
The present invention relates to a method and a control system for dispensing a desired precise amount of a fluid, such as gasoline, by the user of the actuable dispensing mechanism usually associated with the dispensing nozzle of a fluid pump.
2. Description of Prior Art
Various control systems have been developed whereby to control the dispensing of precise dollar amount of fluids from a gas pump. A most common one of these systems, is the one where the pump is only actuable from a central control system so that the intended user of the pump must firstly pay a predetermined amount of dollars for gasoline that he wishes to dispense in his vehicle. Accordingly, the user must firstly go to the control booth associated with a gas station and pay a desired amount of dollars and indicating to the controller which pump he will be utilizing. The user must then return to the pump and actuate the control lever of the gas nozzle and the pump will automatically dispense the exact dollar value paid into the reservoir of the vehicle. Some of the problems caused by such control system, is that often, the dollar amount paid for may not be fully dispensed into the vehicle reservoir as the reservoir becomes filled prior to having dispense the amount of fuel paid for. Accordingly, the user must returned to the control booth to collect the balance of his payment or else drive off having paid more for the gasoline used. Another disadvantage, is that the reservoir of the vehicle often is not filled to capacity by the dollar amount paid as the user does not have full control of the dispensing.
Another problem with automatic fluid dispensing devices of the prior art, is that if the user wishes to place a predetermined dollar value of gasoline in his vehicle, it is very difficult for him to stop the dispensing valve of the nozzle on a precise dollar value as the meter display runs too fast due to the fast flow rates at the dispensing valve. In order to try and solve this problem, various other control systems have been devised such as disclosed in U.S. Pat. No. 4,572,405 or in U.S. Pat. No. 4,254,328. A disadvantage of these systems as disclosed in these patents, is that these systems cannot be adapted to existing gas pumps and still the operator must preset a desired volumeric or dollar amount value in a control computer associated with the pump, and the pump will shut off once that value is attained. The user must then pay the amount stored before he can re-activate the pump. Again, we are then faced with the same problems as above described in having to reset the computer or having to fill the vehicle reservoir to its full capacity. Also, with these systems, the operator must read and comprehend instructions on how to utilize the system and this can be troublesome to certain intended users.